The overall goal of this application is to understand the role of oxidative stress as a potential target in the pathogenesis of chronic beryllium disease (CBD). CBD is an inflammatory hypersensitivity lung disease that occurs in over 800,000 beryllium-exposed workers in the US characterized by pulmonary granulomas. The molecular mechanisms by which beryllium regulates the chronic production of lung inflammation and granuloma formation are unknown. We hypothesize that beryllium induces oxidative stress by altering thiol homeostasis which enhances beryllium specific T cells to produce excessive Th1 cytokines and proliferate, two key features of CBD pathophysiology. Three specific aims are proposed to address the hypothesis. Specific aim 1 will examine the mechanisms by which beryllium stimulates oxidative stress in beryllium specific CD4+ T cells by altering thiol redox status. Specific aim 2 will determine whether beryllium-mediated oxidative stress alters the balance between histone acetyltransferase (HAT) and histone deacetyltransferase (HDAC) activities that modulates inflammation and steroid sensitivity in CBD. This aim will test whether beryllium exposure creates oxidative stress that impairs HDAC activity as a mechanism that amplifies inflammation in CBD. Specific aim 3 will examine the potential therapeutic effect of a 5 aminosalicylic acid in CBD subjects. This last aim will assess a novel new therapy in CBD patients that targets beryllium-mediated oxidative stress and inflammation. The proposed experiments elucidate novel mechanisms that explain the excessive cytokine response to beryllium and pinpoint the role of antioxidant imbalance in CBD and mechanistic approaches to treat CBD.